It is known to apply a layer of open cell thermoplastic foam to the underside of carpets to provide them with non-slip properties. A specific example is the liner disclosed in DE 1560752) (D-S Chemie & Co.). Anti-slip liners are also known which are in the form of open screens and may be stitched to the underside of carpets, as also is a composite liner having outer layers sandwiching a layer of Kraft paper (JP 5237974 in the name of Kanzaki Manufacturing Co. Ltd.). A liner of natural or synthetic latex foam applied directly to the underside of carpets is also known from DE 2028624 (Centrans GmbH).